Is Twitter coming up with an 'Undo Send' button? IANS/New Delhi Reuters file photo The undo button doubles as a progress bar. As millions of Twitter users demand an Edit button to correct spelling errors in their tweets, app researcher Jane Manchun Wong has spotted a new "Undo Send" button that is in the works. The Twitter interface shows familiar "Your Tweet was sent" dialog above a new "Undo" button. Gmail offers a similar option for emails, where it provides a short window to stop messages from being sent after clicking the "Send" button. The undo button doubles as a progress bar, which appears to show you how long you have to undo a tweet before it gets sent," reports The Verge.